Latch mechanism

Abstract

A latch mechanism for a door or the like includes first and second rotatable latch operating members which operate a latching bolt or the like. An axially movable square section spindle extends through complementary holes in both members. In an engaged position, the spindle operates both members when rotated. In a disengaged position, a circular section portion of the spindle registers with a hole in one of the members. In the disengaged position the bolt can be operated by the first member even though the second member may be prevented from rotating by means of pins. The spindle can be moved between engaged and disengaged positions by a push-rod extending out of the door. Thus, when the second member is locked it may be overriden by actuation of the rod and the first member.

I claim: 
     
       1. A latch mechanism for a closure in a frame, comprising latch means for holding said closure in said frame, said latch means including first and second independently rotatable latch operating members each defining a recess, a latch actuating spindle and first and second latch actuating means for applying a latch actuating torque to said spindle from first and second sides of said closure, respectively, wherein said first latch operating member has locking means for preventing rotation of the spindle from the first side, and said second latch operating member has locking means which are operable from the second side to prevent rotation of said second latch operating member, said first latch actuating means being permanently engaged with said spindle to transmit said torque and said spindle being axially displaceable between an engaged position, in which said spindle is engaged in said recess defined by said second latch operating member to transmit said torque, and a disengaged position, in which said spindle and second latch operating member are free to rotate independently. 
     
     
       2. A mechanism as claimed in claim 1, in which said spindle comprises a portion of non-circular section. 
     
     
       3. A mechanism as claimed in claim 1, in which said recess in said second latch operating member is a hole and said spindle also comprises a circular section portion which registers with said hole when said spindle is in said disengaged position. 
     
     
       4. A mechanism as claimed in claim 3 in which said circular section portion is formed between ends of said spindle. 
     
     
       5. A mechanism as claimed in claim 1 in which said spindle is displaceable by means of a push-rod abutting or attached to an end of said spindle remote from said second latch operating member. 
     
     
       6. A mechanism as claimed in claim 1, in which said first latch actuating means comprise a key actuated lock assembly. 
     
     
       7. A mechanism as claimed in claim 1, in which said locking means of said second latch actuating means include pawl means which are engageable with said second latch operating member to prevent actuation of said latch means by said second latch actuating means. 
     
     
       8. A mechanism as claimed in claim 7, in which said pawl means comprise a pin or pins which is/are insertable into said second latch operating member to prevent rotation thereof with respect to said closure to which it is secured. 
     
     
       9. A mechanism as claimed in claim 1, in which said spindle is biased to said engaged position. 
     
     
       10. A door including a mechanism as claimed in claim 1.